[apparmor] [PATCH 5/6] libapparmor: Add aa_splitcon() public function
Tyler Hicks
tyhicks at canonical.com
Thu May 14 05:57:22 UTC 2015
On 2015-05-12 19:01:06, Seth Arnold wrote:
> On Mon, Apr 13, 2015 at 04:56:31PM -0500, Tyler Hicks wrote:
> > Create a new libapparmor public function that allows external code to
> > split an AppArmor confinement context.
> >
> > This is immediately useful for code that retrieves a D-Bus peer's
> > AppArmor confinement context using the
> > org.freedesktop.DBus.GetConnectionCredentials bus method.
> >
> > https://launchpad.net/bugs/1430532
> >
> > Signed-off-by: Tyler Hicks <tyhicks at canonical.com>
>
> This is fine as it is; there's a small typo and I think the manpage should
> emphasize that memory management is up to the caller and don't call free()
> on the mode. Address or not as you wish.
Nice catch on the typo. I changed that locally.
As for the memory management, it feels obvious to me that aa_splitcon()
is simply modifying the con string that you pass to it and no memory
allocations are performed. Am I too close to the code to see how that
might not be clear to others?
>
> Acked-by: Seth Arnold <seth.arnold at canonical.com>
>
> Thanks
Thank you! :)
Tyler
>
> > ---
> > libraries/libapparmor/doc/Makefile.am | 2 +-
> > libraries/libapparmor/doc/aa_getcon.pod | 4 +-
> > libraries/libapparmor/doc/aa_splitcon.pod | 65 ++++++++++++++++++++++++++++
> > libraries/libapparmor/include/sys/apparmor.h | 1 +
> > libraries/libapparmor/src/kernel.c | 17 ++++++++
> > libraries/libapparmor/src/libapparmor.map | 1 +
> > 6 files changed, 87 insertions(+), 3 deletions(-)
> > create mode 100644 libraries/libapparmor/doc/aa_splitcon.pod
> >
> > diff --git a/libraries/libapparmor/doc/Makefile.am b/libraries/libapparmor/doc/Makefile.am
> > index 67de347..73dc1d5 100644
> > --- a/libraries/libapparmor/doc/Makefile.am
> > +++ b/libraries/libapparmor/doc/Makefile.am
> > @@ -5,7 +5,7 @@ PODCHECKER = podchecker
> >
> > if ENABLE_MAN_PAGES
> >
> > -man_MANS = aa_change_hat.2 aa_change_profile.2 aa_getcon.2 aa_find_mountpoint.2 aa_features.3 aa_kernel_interface.3 aa_policy_cache.3
> > +man_MANS = aa_change_hat.2 aa_change_profile.2 aa_getcon.2 aa_find_mountpoint.2 aa_features.3 aa_kernel_interface.3 aa_policy_cache.3 aa_splitcon.3
> >
> > PODS = $(subst .2,.pod,$(man_MANS)) $(subst .3,.pod,$(man_MANS))
> >
> > diff --git a/libraries/libapparmor/doc/aa_getcon.pod b/libraries/libapparmor/doc/aa_getcon.pod
> > index d944fec..32ef61f 100644
> > --- a/libraries/libapparmor/doc/aa_getcon.pod
> > +++ b/libraries/libapparmor/doc/aa_getcon.pod
> > @@ -131,7 +131,7 @@ L<https://bugs.launchpad.net/apparmor/+filebug>.
> >
> > =head1 SEE ALSO
> >
> > -apparmor(7), apparmor.d(5), apparmor_parser(8), aa_change_profile(2) and
> > -L<http://wiki.apparmor.net>.
> > +apparmor(7), apparmor.d(5), apparmor_parser(8), aa_change_profile(2),
> > +aa_splitcon(3) and L<http://wiki.apparmor.net>.
> >
> > =cut
> > diff --git a/libraries/libapparmor/doc/aa_splitcon.pod b/libraries/libapparmor/doc/aa_splitcon.pod
> > new file mode 100644
> > index 0000000..f95109b
> > --- /dev/null
> > +++ b/libraries/libapparmor/doc/aa_splitcon.pod
> > @@ -0,0 +1,65 @@
> > +# This publication is intellectual property of Canonical Ltd. Its contents
> > +# can be duplicated, either in part or in whole, provided that a copyright
> > +# label is visibly located on each copy.
> > +#
> > +# All information found in this book has been compiled with utmost
> > +# attention to detail. However, this does not guarantee complete accuracy.
> > +# Neither Canonical Ltd, the authors, nor the translators shall be held
> > +# liable for possible errors or the consequences thereof.
> > +#
> > +# Many of the software and hardware descriptions cited in this book
> > +# are registered trademarks. All trade names are subject to copyright
> > +# restrictions and may be registered trade marks. Canonical Ltd.
> > +# essentially adhere to the manufacturer's spelling.
> > +#
> > +# Names of products and trademarks appearing in this book (with or without
> > +# specific notation) are likewise subject to trademark and trade protection
> > +# laws and may thus fall under copyright restrictions.
> > +#
> > +
> > +
> > +=pod
> > +
> > +=head1 NAME
> > +
> > +aa_splitcon - split the confinement context into a label and mode
> > +
> > +=head1 SYNOPSIS
> > +
> > +B<#include E<lt>sys/apparmor.hE<gt>>
> > +
> > +B<char *aa_splitcon(char *con, char **mode);>
> > +
> > +Link with B<-lapparmor> when compiling.
> > +
> > +=head1 DESCRIPTION
> > +
> > +The aa_splitcon() function Splits a confinement context into separate label
>
> "Splits" -> "splits"
>
> > +and mode strings. The @con string is modified so that the label portion is NUL
> > +terminated. The enforcement mode is also NUL terminated and the parenthesis
> > +surrounding the mode are removed. If @mode is non-NULL, it will point to the
> > +first character in the enforcement mode string on success.
> > +
> > +=head1 RETURN VALUE
> > +
> > +Returns a pointer to the first character in the label string. NULL is returned
> > +on error.
> > +
> > +=head1 EXAMPLE
> > +
> > + Context Label Mode
> > + ----------------------------- ------------------ -------
> > + unconfined unconfined NULL
> > + /bin/ping (enforce) /bin/ping enforce
> > + /usr/sbin/rsyslogd (complain) /usr/sbin/rsyslogd complain
> > +
> > +=head1 BUGS
> > +
> > +None known. If you find any, please report them at
> > +L<https://bugs.launchpad.net/apparmor/+filebug>.
> > +
> > +=head1 SEE ALSO
> > +
> > +aa_getcon(2) and L<http://wiki.apparmor.net>.
> > +
> > +=cut
> > diff --git a/libraries/libapparmor/include/sys/apparmor.h b/libraries/libapparmor/include/sys/apparmor.h
> > index ca75e5a..6b2148a 100644
> > --- a/libraries/libapparmor/include/sys/apparmor.h
> > +++ b/libraries/libapparmor/include/sys/apparmor.h
> > @@ -58,6 +58,7 @@ extern int aa_change_onexec(const char *profile);
> > extern int aa_change_hatv(const char *subprofiles[], unsigned long token);
> > extern int (aa_change_hat_vargs)(unsigned long token, int count, ...);
> >
> > +extern char *aa_splitcon(char *con, char **mode);
> > /* Protypes for introspecting task confinement
> > * Please see the aa_getcon(2) manpage for information
> > */
> > diff --git a/libraries/libapparmor/src/kernel.c b/libraries/libapparmor/src/kernel.c
> > index b792ac2..5f2d835 100644
> > --- a/libraries/libapparmor/src/kernel.c
> > +++ b/libraries/libapparmor/src/kernel.c
> > @@ -209,6 +209,23 @@ out:
> > }
> >
> > /**
> > + * aa_splitcon - split the confinement context into a label and mode
> > + * @con: the confinement context
> > + * @mode: if non-NULL and a mode is present, will point to mode string in @con
> > + * on success
> > + *
> > + * Modifies the @con string to split it into separate label and mode strings.
> > + * The @mode argument is optional. If @mode is NULL, @con will still be split
> > + * between the label and mode (if present) but @mode will not be set.
> > + *
> > + * Returns: a pointer to the label string or NULL on error
> > + */
> > +char *aa_splitcon(char *con, char **mode)
> > +{
> > + return splitcon(con, strlen(con), mode);
> > +}
> > +
> > +/**
> > * aa_getprocattr_raw - get the contents of @attr for @tid into @buf
> > * @tid: tid of task to query
> > * @attr: which /proc/<tid>/attr/<attr> to query
> > diff --git a/libraries/libapparmor/src/libapparmor.map b/libraries/libapparmor/src/libapparmor.map
> > index 2f440f0..494d2c4 100644
> > --- a/libraries/libapparmor/src/libapparmor.map
> > +++ b/libraries/libapparmor/src/libapparmor.map
> > @@ -80,6 +80,7 @@ APPARMOR_2.10 {
> > aa_policy_cache_make_valid;
> > aa_policy_cache_remove;
> > aa_policy_cache_replace_all;
> > + aa_splitcon;
> > local:
> > *;
> > } APPARMOR_2.9;
> --
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